Trimming machine



Feb. 15, 1938. s. PAINTER 2,108,139

TRIMMING MACHINE Original Filed Feb. 27, 1956 4 Sheets-Sheet l Feb. 15, 1938. R. s. PAINTER 2,108,139

TR IMMING MACHINE ori inal; Filed Feb. 27, 1936 4 Sheets-Sheet 2 2929' 1 a (Iniet R. s. PAINTER 2,108,139

TRIMMING MACHINE Feb. 15, 1938.

Original Filed- Feb. 27, 1936 4 Sheets-Sheet 4 mm 14.; ii i Patented Feb. 15, 1938 UNITED STATES ZdttdSt PATENT OFFICE TRIMMING MACHINE Roy Stanley Painter, Hannibal, Mo., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey 9 Claims.

This invention relates to improvements in trimming machines and has for its primary object to provide a machine particularly adapted to eifect the production of smoothly severed and sharply curved work-edges.

Another object of this invention is to provide a trimming machine, having a work-feeding mechanism, with means for controlling the relative speeds of operation of the work-feeding and work-severing mechanisms.

With the above and other objects in view, as will hereinafter appear, the invention resides in the trimming and work-feeding mechanisms hereinafter described in connection with the accompanying drawings, in which:

Fig. 1 is a rear side elevation, partly in section, of a machine provided with the improved trimmer-actuating mechanism. Fig. 2 is a front end elevation, partly in section, showing the bracketarm and work-supporting post of the machine. Fig. 3 represents a top plan view of the machine, with the bracket-arm shown in longitudi nal section. Fig. 4 is a detail view in side ele vation of a portion of the trimmer-knife actuator bar and its driving stud. Fig. 5 represents a rear side elevation of the machine mounted upon a supporting table provided at the under side thereof with a treadle-controlled electrictransmitter for driving the machine, certain parts of the machine being omitted.

As described in my copending patent application Serial No. 66,012, filed Feb. 27, 1936, of which this application is a division, the present invention is illustrated in the drawings as embodied in a sewing machine to provide a combined stitching and underedge-trimming machine. However, it is to be understood that, in accordance with the present invention, the thread handling mechanisms of the sewing machine may be omitted and that the machine may be employed solely for trimming purposes.

Referring to the drawings, the machine has a frame comprising a bed-plate I, from one end of which rises a work-supporting post 2. Upon the opposite end of the bed-plate is the supporting standard 3 of a bracket-arm 4 which terminates at its free end in a head 5 overhanging the work-supporting post 2. Journaled in the bracket-arm 4 is a horizontally disposed main actuating shaft 6 carrying at one end a combined belt-pulley and balance-wheel l.

The work to be trimmed is preferably intermittently advanced by a drop-feed mechanism including a feed-bar 8 disposed vertically within the post 2 and carrying at its upper end a feed dog 9. The feed-bar 8 derives its actuation from the main shaft 6 in any usual or suitable manner, and preferably so that the feed-dog 9 has one effective work-advancing movement for each rotation of the main-shaft 6. As feeding mechanisms of this character are old and well known in the sewing machine art, it has been deemed unessential to an understanding of the present invention to illustrate and describe any specific form of feed-dog actuating mechanism.

The feed-dog 9 operates through a suitably slotted throat-plate H! secured upon the upper end of the post 2 and is opposed in its work-engaging movement by a presser-roller H. The presser-roller H is carried by the lower end of the usual spring-depressed p-resser-bar l2 journaled for vertical movements in suitable bearings provided in the bracket-arm head 5.

Depending from the under side of the bracketarm 4 is a frame-boss l3 provided with a fiattened lower face affording a seat for a trimmerbracket I6 fixedly secured to said boss by screws I5. J ournaled in suitable bearings provided upon the trimmer-bracket i 4 for endwise reciprocation in a vertically inclined path is a knife-bar 55 carrying, at its lower end, a knife-holder H to which a work-severing element in the form of a straight-edge trimmer-knife I8 is secured by screws I9. While the cutting edge of the knife is straight, it is preferably inclined downwardly in the direction of feed, as illustrated in dotted lines in Fig. 2 of the drawings, the trimmerknife I8 having a path of movement to sever the work substantially parallel to the line of feed. The movement of the trimmer-knife in a vertically inclined path transverse to the plane of the work results in the production of undercut trimmed edges and, accordingly, in the trimming of shoe linings the trimmed edge of the lining is concealed by the beveled edge of the shoe-upper, as is well understood in the art.

As heretofore constructed, the underedge cutting trimmer-knife has usually been actuated from the main shaft of the sewing machine to reciprocate once for each needle reciprocation. When trimming in sharp curves, occurring particularly in shoe production, the work is not only advanced by the feeding mechanism of the machine but is also sharply turned by the operator between successive reciprocations of the trimmer-knife, according to the desired workedge outline. As a consequence, successive straight cuts made by the trimmer-knife intersect each other at an angle and the trimmed edge of the work presents an objectionable appearance. It has been heretofore proposed to overcome this difliculty by reciprocating the trimmer-knife twice foreach rotation of the main shaft of the machine, but this proposal has proven unsatisfactory for several reasons and particularly because of the lack of durability of the trimmer mechanism when operated at the higher speeds of operation of the machine. The present invention obviates the difiiculties inherent in the prior known arrangements in a simple and novel manner.

Suitably secured upon the knife-bar i5 is a collar 20 pivotally connected by a link 25 to an arm 22 of a bracket rigidly carried by the lower end of an actuator bar 23. The actuator bar 2-3 is confined to vertical reciprocation in suitable guide-slots 24 provided in the bracket-arm head 5, said bar 23 having in its outer edge a. notch 25 adapted to receive a coupling-pin 26. The coupling-pin 26 is carried by the free end of a crankarm 2? extending horizontally forward from one end of a rock-shaft 28 disposed substantially parallel to the main shaft 6, said rock-shaft 28 being journaled for rocking and endwise movements in bearing-lugs 29 upon the machine bracket-arm, at the rearward side thereof.

At its end opposite to the crank-arm 2?, the rock-shaft 28 has a circumferential groove 3i) embraced by a suitably notched ear 3| upon one arm 3'2 of an angular hand-lever 32, 33. The hand-lever 32, 33 is pivotally mounted upon a horizontally disposed fulcrum-screw 34 extending transversely of the main shaft 5 and threaded into a boss 35 upon the machine bracket-arm 4. The arm 32 of the hand-lever depends below the bracket-arm 4 so as to be conveniently accessible from the front side of the machine, while the arm 33 of said lever is acted upon by a spring 36 to yieldingly shift the rock-shaft 28 in a direction to effect driving engagement by the coupling pin 25 with the actuator bar 23. A coil-spring 31 has its opposite ends connected to the bracket-arm A and to the knife-bar Hi to retract said knife-bar and thereby to raise the actuator-bar 23 into inoperative positions of said bars, when the handlever 32, 33 is operated to disconnect the coupling-pin 26 from the actuator-bar 23.

Pivotally mounted upon the: trimmer-bracket I4 is a hand-lever 38 which is yieldingly held in inoperative position by a spring 39. The upper end of this lever 38 has a lateral extension 30 adapted, upon operation of said lever, to engage the upper end of the knife-bar t5 and to depress said knife-bar against the action of the spring 3i. Being connected to the knife-bar !6, the actuator-bar 23 is likewise depressed by operation of the hand-lever 33, until the notch 25 of the bar 23 is in alinement with the coupling-pin 25, whereupon said coupling-pin enters the notch 25 under the influence of the spring 36. It will, therefore, be understood that the trimmer-knife carrying bar it may be connected to and disconnected from the rock-shaft 23 at the will of the operator during the operation of the machine.

Extending rearwardly from the rock-shaft 22 and rigidly secured thereto is a rock-arm 4! having a forked free end embracing an eccentric 32 carried by the rotor-shaft d3 of an electric-motor 44. The eccentric 32 is elongated to provide for the requisite sliding movement of the fork of the rock-arm 3! upon said eccentric when the rockshaft 28 is shifted end-wise to disconnect the coupling pin 2% from the actuator-bar 23.

The electric-motor id is disposed so that its rotor-shaft is substantially parallel to and preferably at substantially the same level as the main shaft 6 of the machine, said electric-motor being mounted upon a suitable bracket 45 secured by screws 46 upon the rearward side of the machine bracket-arm 4. The electric-motor has the usual current-controlling switch i? and derives its power from any suitable source, through current leads 48, so that the electric-motor may be operated independently of the operation of the machine feeding mechanism. A guard-bracket 49 houses the eccentric i2 and the forked end of the rock-arm it, said guard-bracket having a supporting shank 58 secured by screws, as 5i, upon the flattened upper face of the bearing-lug 29 which is adjacent to the rock-arm 4!.

The trimming machine is preferably mounted upon a supporting table at the under side of which is disposed trimming machine driving means of any usual or suitable character. As illustrated in Fig. 5 of the drawings, this driving means may comprise an electric-transmitter having a supporting frame 52 suitably secured to the under side of the machine-supporting table 53. Carried by said frame 5.2 is an electric motor 5*; having a rotor-shaft 55 upon which is secured a driving clutch-member 5'6 for rotation therewith. Adapted to frictionally engage the driving clutch member 55 is a driven clutch-member 5'! which is peripherally grooved to form a belt-pulley connected by a belt 58 with the pulley or" the trimming machine. The driven clutch-member 51 may be shifted endwise of the rotor-shaft 55, into frictional engagement with the driving clutchmember 56, by a lever 59 pivotally mounted upon an arm 63 extending from the transmitterframe 52. The lever 59 is connected by an adiustable rod 6| to a suitable treadle 62. By operation of the treadle 62, the lever 59 may be actuated against the action of a spring 83 to bring the clutch-member 5'! into frictional engagement with the clutch-member 5'6, thereby to drive the trimming machine. The speed of operation of the trimming machine may, of course, be varied by permitting slippage between said clutch-members. It is to be understood, however, that the present invention is not limited to the specific form of trimming machine driving means described, as any other suitable speed-controlling power-transmitting device may be employed.

From the foregoing description, it will be understood that when the electric-motor M is in operation, the rock-shaft 2B derives rocking movements from the eccentric 32 carried by the rotor-shaft 43 of the electric-motor. Upon operation of the hand-lever 33, the actuator-bar 23 is coupled to the crank-arm 2'! of said rock-shaft, thereby transmitting reciprocatory movements to the knife-bar l6 which may, at will, be disconnected from its actuating mechanism by manipulation of the hand-lever 32, 33.

The rotor-shaft d3 of the electric-motor 34 rotates at a substantially constant speed, preferably at least equal to the maximum speed of rotation of the main shaft 6 of the trimming machine. Therefore, when the trimming machine is operated at maximum speed and the motor 24 is running, the trimmer-knife l8 reciprocates once for each work-advancing movement of the feeddog 55. However, it is only in substantially straight line trimming that the machine is operated at higher speeds and that the successive straight cut-s performed by the trimmer-knife lfi are in alinement or so nearly in alinement that the trimmed edge of the work presents a smooth appearance.

On the other hand, the trimming of sharp curves is necessarily performed at slow speeds of operation of the machine and, at such slower speeds, the trimmer-knife of the present invention continues to operate at the same speed as before. For example, if the trimmer-knife performs 2800 reciprocations per minute and the machine is operated at a speed of 400 revolutions per minute of the main shaft 6, the trimmerknifewill have seven work-severing strokes for each feeding movement. Consequently, when the work is sharply turned by the operator at the slower speeds of operation of the machine, the intersections of successive cuts performed by the trimmer-knife approach each other so closely that smooth trimming is maintained. The present improvement therefore provides means for actuating the trimming mechanism: at speeds having a ratio variable at will during the operation of the machine.

As illustrated in the accompanying drawings, the trimmer mechanism assembly includes the usual edge-guide and adjusting devices, which are, however, not herein referred to in detail, as a description thereof is considered unessential to an understanding of the present invention.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a trimming machine, the combination with means for supporting and marginally feeding sheet material work in the plane thereof, of trimming means including a reciprocatory plytrimming element having a work-severing cutting edge substantially parallel to the line of feed, and means to vary the work-advancing speed of the feeding means relative to the frequency of reciprocation of the trimming-element without stopping the machine.

2. A trimming machine having a frame including an upstanding work-supporting post and a bracket-arm overhanging said post, a work-feeding mechanism including a feed-dog operating through the free end of said post, a trimmer mechanism supported by said bracket-arm and including a reciprocatory trimmer-element having effective work-severing movements adjacent said feed-dog, and means operable independently of said feeding mechanism for actuating said trimmer mechanism.

3. A trimming machine having a frame including a work-support and a bracket-arm overhanging said work-support, a work-feeding mechanism, a trimmer mechanism supported by said bracket-arm and including a reciprocatory trimmer-element having a work-severing path of movement inclined vertically to said work-support, said trimmer element having its cutting edge substantially parallel to the line of feed, and means to Vary at will the relative speed ratio of said work-feeding and trimmer mechanisms during the operation of the machine.

4. In a trimming machine, the combination with a work-support and mechanism for feeding sheet-material work in the plane thereof, of trimming means including a reciprocatory trimmerelement having a work-severing cutting edge substantially parallel to the line of feed, means for varying the speed of operation of said feeding mechanism relative to the frequency of reciprocation of said trimmer-element without stopping the machine, and means operable at will during the operation of the machine for interrupting the effective action of said trimmerelement.

5. In a trimming machine, the combination with a work-support and mechanism for feeding sheet-material Work in the plane thereof, of trimming means including a reciprocatory trimmer-element having a Work-severing cutting edge substantially parallel to the line of feed, means for varying the speed of operation of said feeding mechanism relative to the frequency of reciprocation of said trimmer-element without stopping the machine, and means operable at will during the operation of the machine for throwing said work-trimming mechanism out of and into effective action.

6. The combination with a trimming machine having a work-feeding mechanism including a feed-dog, of a trimmer mechanism including a reciprocatory knife having effective work-severing movements adjacent said feed-dog, said knife having its cutting edge substantially parallel to the line of feed, an electric motor operable independently of said work-feeding mechanism, and operative connections with said electric motor for reciprocating said knife.

7. The combination with a trimming machine having a work-feeding mechanism, of a reciprocatory trimmer-element having a work-severing cutting edge substantially parallel to the line of 1 feed, an electric motor having a rotor-shaft operable independently of said work-feeding mechanism, an eccentric carried by said rotor-shaft, and actuating connections for reciprocating said trimmer-knife from said eccentric.

8. The combination with a trimming machine having a frame including a work-support and a bracket-arm overhanging said work-support, a rotary actuating shaft journaled in said bracket-arm, and a work-feeding mechanism actuated from said shaft, of a trimmer mechanism supported by said bracket-arm and comprising a reciprocatory trimmer-element having a. worksevering path of movement inclined to said work-support, an electric motor operable independently of and having a rotor-shaft disposed substantially parallel to said actuating shaft, a rock-shaft, means for imparting rocking movements to said rock-shaft from said rotor-shaft, and means connected to said rock-shaft and disconnectible therefrom at will during the operation of the machine for reciprocating said trimme-r-element.

9. In a trimming machine, in combination, a work-advancing feed-dog and a reciprocatory trimmer-element operable at a variable ratio of relative frequencies, means for actuating said feed-dog, means for reciprocating said trimmerelement, and means for varying said ratio comprising controlling means for operating said feed-dog at different speeds.

ROY STANLEY PAINTER. 

